• Title/Summary/Keyword: Hybrid heat exchanger

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A Study on Dynamic Simulation of a Hybrid Parallel Absorption Chiller (병렬식 하이브리드 흡수식 냉온수기 동특성 시뮬레이션 연구)

  • Shin, Young-Gy;Seo, Jung-A;Woo, Sung-Min;Kim, Hyo-Sang
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.630-635
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    • 2008
  • A dynamic model has been developed to investigate the operability of a single and double-effect solar energy assisted parallel type absorption chiller. In the study, main components and fluid transport mechanism have been modeled. Flow discharge coefficients of the valves and the pumps were optimized for the double-effect mode with solar-heated water circulated. The model was run for the single mode with solar energy supply only and the solar/gas driving double effect mode. And the cases of the double mode with and without the solar energy were compared. From the simulation results, it was found that the present configuration of the chiller is not capable of regulating solution flow rates according to variable solar energy input. And the single mode utilizing the solar energy only is not practical. It is suggested to operate the system in the double mode and the flow rate control system adaptive to variable solar energy input has to be developed.

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Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater (상부 코일히터를 갖춘 나선재킷형 태양열 축열조의 성능예측을 위한 CFD 해석모델 개발 및 검증)

  • Baek, Seung Man;Zhong, Yiming;Nam, Jin Hyun;Chung, Jae Dong;Hong, Hiki
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.4
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    • pp.331-341
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    • 2013
  • In a solar domestic hot water (SDHW) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (TST) as hot water. In this study, a computational fluid dynamics (CFD) model was developed to predict the solar thermal energy storage in a hybrid-type TST equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a TST, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the TST. The developed model was validated by the good agreement between the CFD results and the experimental results performed with the hybrid-type TST in SDHW settings.

Dual Mode Phase-Shifted ZVS-PWM Series Load Resonant High-Frequency Inverter for Induction Heating Super Heated Steamer

  • Hisayuki Sugimura;Hidekazu Muraoka;Tarek Ahmed;Srawouth Chandhaket;Eiji Hiraki;Mutsuo Nakaoka;Lee, Hyun-Woo
    • Journal of Power Electronics
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    • v.4 no.3
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    • pp.138-151
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    • 2004
  • In this paper, a constant frequency phase shifting PWM-controlled voltage source full bridge-type series load resonant high-frequency inverter using the $4^{th}$ generation IGBT power modules is presented for innovative consumer electromagnetic induction heating applications, such as a hot water producer, steamer and super heated steamer. The bridge arm side link passive capacitive snubbers in parallel with each power semiconductor device and AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is evaluated and discussed on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency inverter topology, what is called, DE class type, including the variable-power variable-frequency regulation function can expand zero voltage soft switching commutation area even under low output power setting ranges, which is more suitable and acceptable for newly developed induction heated dual pack fluid heaters. Furthermore, even the lower output power regulation mode of this high-frequency load resonant tank inverter circuit is verified so that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

A Novel Induction Heating Type Super Heated Vapor Steamer using Dual Mode Phase Shifted PWM Soft Switching High Frequency Inverter

  • Sugimura, Hisayuki;Eid, Ahmad;Lee, Hyun-Woo;Nakaoka, Mutsuo
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.774-777
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    • 2005
  • In this paper, a constant frequency phase shifting PWM controlled voltage source full bridge-type series load resonant high-frequency inverter using the IGBT power modules is presented for innovative consumer electromagnetic induction heating applications such as a hot water producer, steamer and super heated steamer. The full bridge arm side link passive quasi-resonant capacitor snubbers in parallel with the each power semiconductor device and high frequency AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is discussed and evaluated on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency soft switching PWM inverter topology, what is called class DE type. including the variable-power variable-frequency(VPVF) regulation function can expand zero voltage soft switching commutation range even under low output power setting ranges, which is more suitable and acceptable for induction heated dual packs fluid heater developed newly for consumer power utilizations. Furthermore, even in the lower output power regulation mode of this high-frequency load resonant tank high frequency inverter circuit it is verified that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

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Simultaneous Heating and Cooling Multi-Air Conditioning System for Agricultural Products Management (농수산물 관리를 위한 냉난방 동시형 멀티 에어컨 시스템)

  • Shin, Jin-Seob;Hong, Ji-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.6
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    • pp.65-70
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    • 2020
  • In this paper, to establish a high-efficiency air-conditioning and heating system, we developed a simultaneous air-conditioning and heating system that can do both air-conditioning and heating at the same time. It was applied to hybrid plant plants to enable automation of complex farms. For this purpose, the heat exchanger, which functions as a condenser during heating, was required to function as an evaporator during cooling so that air conditioning and heating could be implemented simultaneously. For experiments, the simultaneous air conditioning system for heating and cooling was produced and applied to the plant factories in the farms so that plants could be grown, stored, and dried. As a result, a single system was able to control the temperature environment of agricultural products with an energy-saving system that simultaneously resolves heating and cooling. Therefore, efficient crop management was possible by implementing an air conditioning system that did not require installing air conditioners and boilers at the same time.